Book Image

Solidity Programming Essentials

Book Image

Solidity Programming Essentials

Overview of this book

Solidity is a contract-oriented language whose syntax is highly influenced by JavaScript, and is designed to compile code for the Ethereum Virtual Machine. Solidity Programming Essentials will be your guide to understanding Solidity programming to build smart contracts for Ethereum and blockchain from ground-up. We begin with a brief run-through of blockchain, Ethereum, and their most important concepts or components. You will learn how to install all the necessary tools to write, test, and debug Solidity contracts on Ethereum. Then, you will explore the layout of a Solidity source file and work with the different data types. The next set of recipes will help you work with operators, control structures, and data structures while building your smart contracts. We take you through function calls, return types, function modifers, and recipes in object-oriented programming with Solidity. Learn all you can on event logging and exception handling, as well as testing and debugging smart contracts. By the end of this book, you will be able to write, deploy, and test smart contracts in Ethereum. This book will bring forth the essence of writing contracts using Solidity and also help you develop Solidity skills in no time.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Storage and memory data locations


Each variable declared and used within a contract has a data location. EVM provides the following four data structures for storing variables:

  • Storage: This is global memory available to all functions within the contract. This storage is a permanent storage that Ethereum stores on every node within its environment.
  • Memory: This is local memory available to every function within a contract. This is short lived and fleeting memory that gets torn down when the function completes its execution.
  • Calldata: This is where all incoming function execution data, including function arguments, is stored. This is a non-modifiable memory location.
  • Stack: EVM maintains a stack for loading variables and intermediate values for working with Ethereum instruction set. This is working set memory for EVM. A stack is 1,024 levels deep in EVM and if it store anything more than this it raises an exception.

The data location of a variable is dependent on the following two factors:

  • Location...